Defeating Dandruff

April 27, 2012 -- Doctors have been scratching their heads over how to treat bad cases of dandruff for more than century.

Over-the-counter shampoos and scalp treatments can help when dandruff is mild, says Thomas L. Dawson, PhD, a scientist at Procter & Gamble who works on Head & Shoulders shampoo. But they may not always benefit people with badly flaking and irritated scalps.

Now, a raft of new research, including a new study published in the Journal of Medicinal Chemistry, suggests that scientists may be close to heading off the fungus that causes the problem in the first place.

Getting to the Root of Dandruff

Malassezia globosa is a fungus present on the skin of many newborns. Often, it lives harmlessly in the top layer of skin without causing any problems.

But for an estimated 50% of the population, it burrows into a hair follicle and sets up shop. And for reasons doctors don't fully understand, the body reacts. Skin cells can become irritated and shed roughly four times faster than normal, dropping off in days instead of once a month. The scalp can become irritated and itchy.

Scientists have long known that malassezia was the culprit behind dandruff, but because it is difficult to grow in a laboratory, it was tough to study.

In 2007, Dawson and a team of researchers at Procter & Gamble sequenced the Malassezia genome. That discovery gave scientists a new way to study the organism, and it sparked a resurgence of interest in finding ways to stop the problematic fungus.

"That was really the key in the lock that opened the door to all this work," Dawson says.

In the latest study, researchers in Italy and the U.K. were able to use the genome to look for proteins that might be critical to malassezia's growth.

"When you inhibit this enzyme, the organism cannot grow well, so the organism dies," says Claudiu T. Supuran, a chemistry professor at the University of Florence.

What's more, the enzyme can be stopped by antibacterial drugs called sulfonamides or sulfas, which have been around since the 1930s.

Supuran and his colleagues tested that idea by giving six mice bad cases of dandruff and then treating them with a sulfa drug. Four out of the six mice showed improvement, suggesting that sulfa drugs may be a new weapon against dandruff.